My pleasure, glad to help. So many others here at BYC have helped me, it's the least I can do. So glad she's doing better. If you saw the possible injury, then that very well could be it. I can say that chickens (and birds in general) run into things in flight a lot, especially while escaping from something (each other, predators, whatever). It's possible she got a good bang on the head and that's the reason for her closed eye. But, that could also be a coincidence? It's so hard to say, isn't it? Anyway, you're doing all the right things, have her isolated with her buddy, keeping an eye on her, no strange discharges coming from her eye, etc. I'd say you've done and are doing all that you can.
One thing that you made me think about is antibiotics. Others here might recommend having antibiotics on hand. I have Durmamycin (tetracycline) because I needed it awhile back for a respiratory infection and have what was left over. Each of us considers meds differently and how quickly we move from symptoms to administering meds. I am not anti-meds at all but I don't go there immediately. Mostly, because it's so hard to diagnose chicken illnesses as so many things have very similar symptoms. Antibiotics don't do a thing for illnesses caused by a virus, for example. But if it's caused by a bacteria, an antibiotic might help. There are problems dosing with antibiotics when they're not needed such as it can enable the bacteria to build resistance to the antibiotic, rendering stronger strains in the future. Antibiotics also kill bacteria in the chicken (or in people too for that matter) indiscriminately meaning it kills not only the bad bacteria causing illness but all the good bacteria inside the animal too. And so many bacteria are healthy/necessary and good. Bacteria sort of gets a bad rap when most of it's not bad and required for survival. But by killing off the good bacteria in an animal, it lowers their natural immunity and makes them more susceptible to other illnesses.
Anyway... I scanned a few of the eye infections in this book and most are caused by a virus but a few are caused by bacteria. Your chicken sounds like she's on the up swing but if she takes a turn for the worst, and you have no real way of nailing down what illness she has, you could go the antibiotic route. Again, I'm not recommending for or against this, just stating that it's an option. Something for you to decide in your own way and maybe do more research on as you see fit.
Hope this helps,
Guppy